Table 2. Comparisons of CDC, M_f, M_l, and GFT peak ILI values.

Influenza Season	Year	Week	ILI Value	Referent CDC ILI Value*	% Difference from CDC ILI Value	Peak Agrees with CDC
2007–2008
CDC Peak	2008	7	5.98
Mf Peak	2008	8	4.94	5.62	0.68	N
Ml Peak	2008	7	4.43	5.98	−1.55	Y
GFT Peak	2008	8	5.81	5.62	0.19	N
2008–2009
CDC Peak	2009	7	3.57
Mf Peak	2009	12	3.48	2.43	−1.05	N
Ml Peak	2009	12	3.33	2.43	0.90	N
GFT Peak	2009	8	3.50	3.37	0.13	N
2009–2010
CDC Peak	2009	43	7.72
Mf Peak	2009	43	8.36	7.72	−0.64	Y
Ml Peak	2009	44	8.66	7.55	1.11	N
GFT Peak	2009	43	7.11	7.72	−0.61	Y
2010–2011
CDC Peak	2011	4	4.55
CDC Peak	2011	6	4.55
Mf Peak	2011	6	5.84	4.55	−1.29	Y
Ml Peak	2011	6	5.73	4.55	1.18	Y
GFT Peak	2011	6	4.08	4.55	−0.47	Y
2011–2012
CDC Peak	2012	10	2.39
Mf Peak	2012	7	2.68	2.24	−0.44	N
Ml Peak	2012	7	2.85	2.24	−1.55	N
GFT Peak	2011	52	2.86	1.74	1.12	N
2012–2013
CDC Peak	2012	51	6.07
Mf Peak	2012	51	5.31	6.07	0.76	Y
Ml Peak	2012	52	5.40	4.65	−1.55	N
GFT Peak	2013	2	10.56	4.52	6.04	N

ILI: Influenza-like illness, CDC: Centers for Disease Control and Prevention.

M_f: Full model, M_l: Lasso model, GFT: Google Flu Trends.

*Referent values are CDC ILI values for the corresponding week of the estimated ILI peak for M_f, M_l, and GFT.